Two months after rolling out hashtags — key words in posts that are marked by “#” – Facebook is experimenting with new ways to make them useful.

The social network has begun testing a “trending” topics section in the homepage news feed of its website. The section — similar to rival Twitter’s “trends box — showcases topics, including hashtags, that are currently popular on the site.

“We are running a small test of a unit on News Feed,” she said. “Right now it only available to a small percentage of US users and it is still in the early stages of development.”

She said Facebook will disclose more details if it decides to release the feature more broadly.

The test, which began on Thursday, highlights the escalating brawl between Facebook and Twitter to be the dominant destination for live, real-time conversations online. It is a critical battleground: The company that becomes the top hub for chatter around news events and TV shows will have a key advantage in wooing advertisers — especially as brands consider spending more money on mobile and desktop ads instead of television ads.

Twitter, which has featured hashtags and trending topics for years, has long been seen as the destination for tracking emerging conversations.

Facebook, however, has made a big play for the space this year, rolling out hashtags in June and then earlier this month testing a “trending” section for its mobile website. The company has also heavily promoted data that describes mentions about news events and television shows, such as episodes of HBO’s Game of Thrones.

The latest test, for users on desktop Web browers, highlights trending topics on the upper-right corner in a user’s news feed, a very prominent piece of real estate.

Like Twitter, Facebook’s trending section will reflect popular hashtags and topics that are generating a lot of conversation. For example, Facebook’s algorithm would group all public conversations mentioning #MLK and “Martin Luther,” under one topic in the trending section, such as “Martin Luther King, Jr.”